- Broadcast engineering and IT related links and stuff. Maybe some music, films and other things.

Sunday, April 15, 2007

My standard recruitment questions for engineers

Video:

A DigiBeta machine has an 8-Field lock switch – why is this an anomaly on such a VTR and what does the switch do?

This question would really sort out the sheep from the goats! This shows if they know anything about PAL and how VTRs lock their servos. If they can give a credible explanation that uses the phrase “vertical interval sub-carrier (VISC)” and they appreciate that the VTR can re-encode the PAL o/p with the same phase of sub-carrier that was used to decode it then give them the job there and then!

Audio:

0dBu = 4PPM = -18dBfs

What do these expressions mean and why is this equation significant?

Do they know anything about audio measurements and how analogue and digital levels relate? If they can explain the terms dBu and dBfs then all the better.

What is the significance of balanced audio and why shouldn’t you plug unbalanced equipment into a balanced distribution?

Kind of important – if they mention “common mode rejection” in relation to balanced audio hire them! If they don’t know about the risks of unbalancing a whole facility then worry!

Networks:

Hub, Switch, Router.

What are the differences and similarities between these gadgets? How would you use each?

The whole world runs on packet switched networks – do they know anything about it?

Electronics:

A line-drive amplifier has a gain of 20dBs on zero level – how big a power supply would such an amp need?

Do they know that 0dBu is 0.773v? Do they know that 20dBs is approx a ten-fold increase in power? If they can do the calculation don’t let them escape!

What is the significance of technical and domestic (“cooking”) mains – why shouldn’t equipment powered by one distribution be connected to equipment powered by the other?

Do they appreciate earth distribution and the danger of putting mains hum over every feed in a facility?

Avid:

On a Unity server what is the difference between ‘Allocation Groups’ and ‘Workspaces’?

Any Unity configuring experience (or more importantly have they taken an interest in an installation they may have had to look after?)

What is a Media Database and why would you ‘trash’ it. What other things might you ‘trash’?

When you can measure what you are speaking about, and express it in numbers, you can know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind: it may be the beginning of knowledge but you have scarcely, in your thoughts, advanced to the stage of science.